This non-provisional application claims priority under 35 U.S.C. § 119(a) to Korean Patent Application No. 2003-30110 filed on May, 13, 2003 which is herein incorporated by reference.
1. Field of the Invention
The present invention relates to a method for forming a highly electrically conductive metal pattern, and an electromagnetic interference filter (hereinafter, abbreviated as “EMI filter”) using a metal pattern formed by the method. More particularly, the present invention relates to a method for forming a metal pattern which comprises the steps of (i) coating a photocatalytic compound onto a substrate to form a photocatalytic film, (ii) selectively exposing the photocatalytic film to light to form a latent pattern acting as a nucleus for crystal growth, and (iii) plating the latent pattern to grow metal crystals thereon; a metal pattern formed by the method; and an EMI filter comprising the metal pattern. According to the method of the present invention, a highly electrically conductive metal wiring pattern can be rapidly and efficiently formed, when compared to conventional methods. In addition, the EMI filter comprising the metal pattern not only exhibits excellent performance, but also is advantageous in terms of low manufacturing costs and simple manufacture processes. Accordingly, the EMI filter can be broadly applied to flat panel display devices, such as plasma display panels (PDPs).
2. Description of the Related Art
In recent years, with a drastically increasing demand for display devices, including plasma display panels as wall-mounted televisions, there has been considerable discussion about static electricity and harmful electromagnetic waves emitted from the display devices. For example, Japanese Patent Laid-open No. Hei 1-278800 discloses a method for forming a transparent electrode on a display plane of a screen by a sputtering or deposition process; Japanese Patent Laid-open No. 2000-323890 describes a method for forming a mesh pattern by coating an adhesive agent layer-laminated conductive film onto a transparent substrate and for forming a pattern on the conductive film using a photoresist or a printable resist material and metal-etching. According to the former method, the film has a thickness between 100 Å and 2,000 Å in order to shield harmful electromagnetic waves and to ensure the transmittance of visible light emitted from PDP devices. However, within the range of the film thickness, the electromagnetic wave shielding effect is unsatisfactory (FIG. 1). In addition, the latter method has problems of high manufacturing costs and an additional need for a near-infrared film to operate remote controllers for household electronic products (FIGS. 2 and 3). As alternative examples, Japanese Patent Laid-open Nos. Hei 5-16281 and 10-72676 disclose a method for manufacturing an electromagnetic wave shielding film involving the following steps: laminating a transparent resin layer onto a transparent substrate, e.g., made of polycarbonate; electroless copper plating on the resin layer; and forming a mesh pattern thereon by an etching process, e.g., microphotolithography (FIG. 4). Although this method is advantageous for easy treatment of the metal thin film, it is disadvantageous in that the composition of an etching solution, the etching temperature and the etching time are difficult to manage upon etching by photolithography. Furthermore, Japanese Patent Laid-open No. 2001-168574 suggests a method for forming a mesh pattern without undergoing etching. According to this method, a transparent resin film containing reducing metal particles (electroless plating catalyst) is laminated onto a transparent substrate; a catalyst present at an opening portion formed on a mesh pattern is deactivated or washed out with a dissolution agent; an electromagnetic wave or electronic beam is irradiated thereto; and finally only the catalyst is subjected to electroless plating to form an electromagnetic wave shielding film on the mesh pattern. However, the method involves the use of additional processes, e.g., the catalyst present at the opening portion must be deactivated by an inkjet process, or a pattern must be formed using a photoresist before deactivation. Accordingly, the overall process conditions of the method are complicated despite the absence of etching.
Thus, there exists a need in the art for a method for forming a highly electrically conductive metal wiring pattern, wherein the metal wiring pattern can be rapidly and efficiently formed in a simple manner without the necessity of additional processes, e.g., a process for forming a metal thin film requiring high vacuum and high temperature conditions, or an exposure process for forming a fine pattern and a subsequent etching process. There is also a need for a method for forming a metal pattern which can be used to manufacture an EMI filter with excellent performance.